Sheeler, W. D. (1978). Welcome to ENGLISH: WORKBOOK 4. English Language Services.
Lua i Stíl Chicago (17ú heag.)Sheeler, Willard D. Welcome to ENGLISH: WORKBOOK 4. English Language Services, 1978.
Lua MLA (8ú heag.)Sheeler, Willard D. Welcome to ENGLISH: WORKBOOK 4. English Language Services, 1978.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.